The basic technique of Chinese cooking consists of stir-fry, quick-fry, shallow-fry, deep-fry, roasting, simmering, braising, quick-boil, boiling, steaming and slippery-fry etc. Among them the stir-fry employs oil and metal as main medium for heat transferring, in which the amount of oil is relatively small, the temperature of oil during cooking is relatively low, and there usually is a step for quickly seasoning after raw material being well cooked.
According to the heating feature the above stir-fry can be divided into oil stir-fry and lasting stir-fry. The oil stir-fry is most widely used and includes two basic steps: oil-frying and stir-frying. Cooking materials are fried well in oil in the step of oil-frying. In this step the key factor is to control the change of oil temperature when cooking materials being put into a pot with considering the amount of cooking materials, the amount of oil, the intensity of heating, and the requirements of cooking material for the temperature of oil. The cooking materials should be quickly stirred and dispersed after being put in order to prevent the cooking materials from shedding of starch or egg-white or from massing. Then the dispersed cooking materials should be taken out immediately and make oil leached. In the step of stir-frying, the cooking materials are quickly heated in a medium or high heating intensity with moderate or little oil (which may include water, soup and water starch etc) or metal itself (such as that of a pot or a cooking container) as medium for heat transferring, and simultaneously the cooking materials are quickly stirred, turned over, and mixed with a stirring tool and/or through the relative movement between the cooking materials and the pot to ensure the taste, color and effect of the finished dish (such as delicious, tender, crisp, smooth, tasty, and/or mellow). During the stir-frying, which is the last step of oil stir-fry, the oil-fried materials and seasonings should be mixed. The more quickly the stir-frying is done, the more tender the finished dish will become. It is important to ensure the strong fire, quick action and accurate seasoning. For many dishes prepared by oil stir-fry it is necessary to fry shallot, ginger, garlic or other seasonings in dry manner before the step of stir-frying. There are three methods for putting starch on cooking materials in oil stir-fry, including mixed pouring, successive pouring, and pre-pouring. The first one is to put all necessary seasonings and starch in a small bowl, mix them completely, and then pour the obtained mixture onto the oil-fried materials or into a pot when cooking materials have been cooked with subsequent quick stirring. The second one is to put seasonings and soup in turn into a pot after the oil-fried materials being put, and then pour water starch after boiling. The third one is to put all necessary seasonings and soup into a pot and then put the oil-fried materials into it after it is boiled. It is necessary to accurately control on the oil's temperature, the heating intensity, the time of material-feeding and the stirring frequency for preparing dishes with wonderful color, odor and taste.
New kitchen devices have been developed in recent years, such as automatic electric rice cooker, etc. However these kinds of kitchen devices are only used for solving certain problems. They almost can do nothing for performing cuisine, especially the Chinese cuisine, such as performing various cuisine techniques, especially those of stir-fry, the control on duration and degree of heating, various basic operations of cuisine, etc.
The fundamental problems of automatic cooking are to replace various manual actions with automatic or semiautomatic mechanical actions, adopt artificial intelligence method on automatic or semiautomatic devices, and perform various basic cuisine techniques automatically or semi-automatically, such as stir-fry, quick-fry, shallow-fry, deep-fry, roasting, simmering, braising, quick-boil, boiling, steaming and slippery-fry, etc.
Some cooking devices sold in the market, such as micro-wave oven, are said to be configured with tens of cuisine programs with the capability of making major styles of cooking. Actually the micro-wave oven is not fit for Chinese cuisine, even for western cuisine, and such kind of cooking devices could not implement many basic cooking actions such as auto-feeding, automatic stirring, etc. For the control of duration and degree of heating alone, different controls on duration and degree of heating are required in different styles of dishes, different material selections and different preparation methods. Therefore only tens of programs that programmed according to styles of cooking or categories cannot cover all of these requirements for duration and degree of heating. Take “shredded pork with garlic sauce” for instance. Different material selections (such as loins and meet of leg), different preparation styles (horizontal cutting and vertical cutting, small parts and big parts etc) and different amount of materials will require different control on duration and degree of heating and operations. Thus the same cooking procedure cannot achieve the same cuisine effects under different conditions.
A fully automatic cooking device is published in Chinese patent 01230251.1, which discloses how to separate materials from oil using oil-material separator. This oil-material separator contains empty an oil box 45 and a cover 44 consisting of net/oil pump on the top of the empty oil box 45. The cover 44 is opened while separating oil from materials, the pot 47 is moved to the top of the empty oil box 45 and rotated until it touches the inner net of cover 44. The cooking materials are stopped by the net and the oil pours into the empty oil box 45. Although this oil-material separator can remove oil the cooking materials are kept in the pot. Therefore the oil on the cooking materials is difficult to leach thoroughly, which may cause starch can not be covered on cooking materials in the subsequent stir-frying and seasoning. If the oil is forced to be filtrated completely it is difficult to avoid the cooking materials being moved to cover 44 along with oil. If this happens, the device published in this patent cannot return these materials to the pot. Even when the oil is filtrated completely and all cooking materials are kept in the pot, there still exists some vital problems for cuisine. As we know, the step of oil-frying is undertaken in the warm oil while the step of stir-frying should be performed under high heating intensity. Usually there exists a procedure of heating the pot with strong fire after oil-frying, and if the cooking materials are left in the pot 47 at this time, then they will be overcooked, losing the wonderful taste of oil stir-fry. The shallot, ginger and garlic (fry very quickly over hot fire) or other seasonings are quickly fried before stir-frying for many dishes of oil stir-fry, and if the cooking materials are left in the pot 47 this kind of procedure are almost impossible to be conducted. In addition, no mechanism which can give rapid and effective material dispersing is equipped with this device. In addition the dispersing function is still impossible in it. Therefore, it is obvious that the technique of oil stir-fry cannot be realized by the device disclosed in this patent.
Chinese patent 98232654.8 opens an automatic cooking device of Chinese dishes with the function of automatically turning a pot's bottom over, which can be used to pour cooking materials out of the pot automatically. But the device disclosed in this patent cannot be used to perform oil stir-fry because no dispersing mechanism, oil leaching mechanism or re-feeding mechanism is equipped with it.